1. Field of the Invention
The present invention relates to a vibration type driving apparatus that causes a moving member that is in contact with a plurality of vibration members to move in a plurality of different directions. In particular, the present invention relates to a vibration type driving apparatus that is suitable for use in a driving table or a mechanism for correcting motion blur of an optical apparatus, such as a camera and a binocular.
2. Description of the Related Art
Hitherto, the following driving apparatus has been proposed in Japanese Patent Laid-Open No. 2009-225503.
That is, the driving apparatus includes a plurality of vibration members, a securing section, and a moving member. The vibration members are combinations of elastic members and electro-mechanical energy conversion elements. The securing section holds the plurality of vibration members. The moving member contacts the plurality of vibration members, and is frictionally driven in a plurality of different directions.
Accordingly, the driving apparatus is formed so that the moving member that contacts the plurality of vibration members can move in the plurality of different directions.
Such a driving apparatus will be described in more detail with reference to FIGS. 18A and 18B.
In FIG. 18A, vibration members 101 to 103 generate driving forces in different directions (that is, in the directions of arrows M11 to M13), and cause a moving member 104 to move.
These driving forces act upon the moving member 104 as a combination of forces vectors, causing the moving member 104 to move in the direction of arrow Ms shown in FIG. 18B.
Although, in FIGS. 18A and 18B, the example in which the vibration members generate driving forces in the directions of arrows M11 to M13 so that the moving member moves in the direction of arrow Ms is illustrated, it is possible to move the moving member in any direction on the basis of the combination of force vectors of the driving forces that are generated by the respective vibration members.
PCT Japanese Translation Patent Publication No. 2007-524339 proposes a positioning apparatus that can drive a moving member in a plurality of different directions using a plurality of vibration members, and a method of reducing a load.
In PCT Japanese Translation Patent Publication No. 2007-524339, when the moving member is driven in the plurality of directions using the plurality of vibration members, a load applied to the vibration members is reduced in the following way.
In order for at least one of the plurality of vibration members for moving the moving member to apply a parallel force to a surface of the moving member, and in order for at least one of any of the other vibration members to apply a vertical vibration (a vibration mode for push-up moving) to the surface of the moving member, these are controlled at the same time, to reduce load.
When a period of vertical vibration is controlled, and the parallel force is applied to the moving member, the vibration member that applies the vertical vibration is moved away from the moving member.
In Japanese Patent Laid-Open No. 2009-225503, when, for example, a vibration member that does not apply a force to the moving member and that is disposed in a direction orthogonal to a vibration member that applies a force in a direction of movement of the moving member is in contact with the moving member, this acts as a load on the movement of the moving member.
In contrast, in PCT Japanese Translation Patent Publication No. 2007-524339, a load on the movement of the moving member is reduced by causing the vibration members other than the vibration member that applies a force that is parallel to the surface of the moving member for moving the moving member to only apply vertical vibration to the surface of the moving member.
However, when only the vertical vibration is applied to the moving member, the vibration members and the moving member cannot be completely out of contact with each other. Therefore, it is difficult to completely eliminate the load. In addition, even with the structure of an embodiment discussed in PCT Japanese Translation Patent Publication No. 2007-524339 (in which, when a timing of applying only the vertical vibration to the surface of the moving member is controlled, and a parallel force is applied to the surface of the moving member, the vibration member that applies the vertical vibration to the surface of the moving member is moved out of contact with the moving member), it is difficult to constantly keep them out of contact with each other.
That is, in such a structure, the state of contact of the moving member with the vibration members depends upon, for example, the shapes of contact surfaces, vibration amplitudes of the vibration members, the mass of the moving member, the rigidities of the contact surfaces between the moving member and the vibration members. Accordingly, it is difficult to constantly keep them out of contact with each other.
Therefore, even in PCT Japanese Translation Patent Publication No. 2007-524339, contact between the moving member and the vibration member that applies a vertical vibration to the surface of the moving member becomes a load on the movement of the moving member.